OBJECTIVES: 1. A series of structurally distinctive chemical compounds have been shown in this lab to have important biochemical properties: they serve as specific inhibitors of squalene oxide cyclase in cholesterol biosynthesis. We will utilize the novel function of these inhibitors to study regulation of cholesterol metabolism. 2. A specific cholesterol-requiring mutant has been isolated in this lab. We will characterize the biochemical properties of this mutant in detail. 3. The enzyme which catalyzes the formation of cholesterol ester from cholesterol has been solubilized in this lab. We will carry out extensive enzymology of this enzyme in detail.